A Cook County judge is expected to rule Friday afternoon whether to put a temporary halt to Cook County's penny-per-ounce tax on sweetened beverages. The tax is set to go into effect Saturday.

Earlier this week the Illinois Retail Merchants Association and several grocers filed a lawsuit seeking to block the tax, which they argue is unconstitutional and too vague.

County officials have said the new tax is needed to pay for county services and will benefit the public's health over time. Meanwhile, many retailers oppose the tax, which would apply to a wide variety of sugar- and artificially sweetened beverages.

The hearing on whether to issue a temporary restraining order occurred Thursday afternoon before Judge Daniel Kubasiak.

Fountain drinks and those in sealed containers would be taxed. Exempt from the tax are sweetened coffee drinks like those made at coffee shops and purchases made with food stamps.

It's those inconsistencies, among other things, to which the beverage sellers object. They allege that, under the Illinois Constitution, similar objects should be taxed uniformly. But under the sweetened beverage tax, sweetened beverages in a bottle, or from a fountain machine, are taxable, while on-demand, custom-sweetened beverages, such as sweetened iced tea mixed by a server or barista, or a hand-made Frappuccino, aren't subject to the tax. The health consequences of both types of drinks, however, are the same, the lawsuit says. Also, calculating taxes on fountain drinks would be difficult because the amount of ice might vary and the cup might be refilled, the lawsuit says.

A look at the numbers behind Cook County's new soda tax. How will the tax work and how much will it cost consumers? (Phil Geib / Chicago Tribune)

A look at the numbers behind Cook County's new soda tax. How will the tax work and how much will it cost consumers? (Phil Geib / Chicago Tribune)

David Ruskin, a Horwood Marcus Berk lawyer representing the retailers, also said there currently isn't a system in place for refunds to occur should the tax eventually be found unconstitutional. That's why a temporary restraining order is needed, he said.

A lawyer for the county said the tax is expected to generate $17 million a month in revenues in fiscal 2017.